var $ = function (id) {

    return "string" == typeof id ? document.getElementById(id) : id;

};

var Bind = function(object, fun) {

    return function() {

        return fun.apply(object, arguments);

    }

};

function AutoComplete(obj,autoObj,arr){

    this.obj=$(obj);        //输入框

    this.autoObj=$(autoObj);//DIV的根节点

    this.value_arr=arr;        //不要包含重复值

    this.index=-1;          //当前选中的DIV的索引

    this.search_value="";   //保存当前搜索的字符

}

AutoComplete.prototype={

    //初始化DIV的位置

    init: function(){

        this.autoObj.style.left = this.obj.offsetLeft + "px";

        this.autoObj.style.top  = this.obj.offsetTop + this.obj.offsetHeight + "px";

        this.autoObj.style.width= this.obj.offsetWidth - 2 + "px";//减去边框的长度2px

    },

    //删除自动完成需要的所有DIV

    deleteDIV: function(){

        while(this.autoObj.hasChildNodes()){

            this.autoObj.removeChild(this.autoObj.firstChild);

        }

        this.autoObj.className="auto_hidden";

    },

    //设置值

    setValue: function(_this){

        return function(){

            _this.obj.value=this.seq;

            _this.autoObj.className="auto_hidden";

        }

    },

    //模拟鼠标移动至DIV时，DIV高亮

    autoOnmouseover: function(_this,_div_index){

        return function(){

            _this.index=_div_index;

            var length = _this.autoObj.children.length;

            for(var j=0;j<length;j++){

                if(j!=_this.index ){

                    _this.autoObj.childNodes[j].className='auto_onmouseout';

                }else{

                    _this.autoObj.childNodes[j].className='auto_onmouseover';

                }

            }

        }

    },

    //更改classname

    changeClassname: function(length){

        for(var i=0;i<length;i++){

            if(i!=this.index ){

                this.autoObj.childNodes[i].className='auto_onmouseout';

            }else{

                this.autoObj.childNodes[i].className='auto_onmouseover';

                this.obj.value=this.autoObj.childNodes[i].seq;

            }

        }

    }

    ,

    //响应键盘

    pressKey: function(event){

        var length = this.autoObj.children.length;

        //光标键"↓"

        if(event.keyCode==40){

            ++this.index;

            if(this.index>length){

                this.index=0;

            }else if(this.index==length){

                this.obj.value=this.search_value;

            }

            this.changeClassname(length);

        }

        //光标键"↑"

        else if(event.keyCode==38){

            this.index--;

            if(this.index<-1){

                this.index=length - 1;

            }else if(this.index==-1){

                this.obj.value=this.search_value;

            }

            this.changeClassname(length);

        }

        //回车键

        else if(event.keyCode==13){

            this.autoObj.className="auto_hidden";

            this.index=-1;

        }else{

            this.index=-1;

        }

    },

    //程序入口

    start: function(event){

        if(event.keyCode!=13&&event.keyCode!=38&&event.keyCode!=40){

            this.init();

            this.deleteDIV();

            this.search_value=this.obj.value;

            var valueArr=this.value_arr;

            valueArr.sort();

            if(this.obj.value.replace(/(^\s*)|(\s*$)/g,'')==""){ return; }//值为空，退出

            try{ var reg = new RegExp("(" + this.obj.value + ")","i");}

            catch (e){ return; }

            var div_index=0;//记录创建的DIV的索引

            for(var i=0;i<valueArr.length;i++){

                if(reg.test(valueArr[i])){

                    var div = document.createElement("div");

                    div.className="auto_onmouseout";

                    div.seq=valueArr[i];

                    div.onclick=this.setValue(this);

                    div.onmouseover=this.autoOnmouseover(this,div_index);

                    div.innerHTML=valueArr[i].replace(reg,"<strong>$1</strong>");//搜索到的字符粗体显示

                    this.autoObj.appendChild(div);

                    this.autoObj.className="auto_show";

                    div_index++;

                }

            }

        }

        this.pressKey(event);

        window.onresize=Bind(this,function(){this.init();});

    }

}
